1. Field of the Invention
This invention relates to a thyristor with a multi-layer semiconductor body with a pnpn layer sequence and also to a method for its manufacture.
2. Prior Art
Thyristors of this type are known, for example, from the book "Thyristor Physics" by a Adolph Blicher, Springer-Verlag, New York, 1976, pages 198 through 200, particularly FIG. 14.1. Thyristors of the type initially cited are disclosed in "Semiconductor Power Devices" by S. K. Ghandhi, John Wiley & Sons, London, 1977, page 81, particularly FIG. 2.34b, the edge of said thyristors being doubly slanted so that, proceeding from the upper and lower boundary surface, it respectively tapers in a direction toward a plane lying between said boundary surfaces. The minimum cross-sectional surface of the thyristor lies in said plane, when this is based only on cross-sections parallel to the pn junctions. One thereby also speaks of thyristors whose edge describes two positive angles with the upper and lower boundary surface, or of thyristors with a dove-tail profile.
The doubly slanted edge of such a thyristor is produced by means of the influence of a sand jet conducted obliquely relative to the boundary surfaces. Subsequently, however, the edge must be subjected to an etching process in order to eliminate the short-circuits which bridge the pn junctions and which arose as a result of such a mechanical processing operation.